ETS-VI Magnetometer Data Plots

The Satellite

The ETS-VI satellite was launched on August 28, 1994 and operated until July 5, 1996. The satellite was three-axis stabilized, had a perigee of 2.3 Re, an apogee of 7.1 Re, an inclination of 13.4 degrees, and an orbital period of 14.4 hours.

The Magnetometer

The satellite carried a triaxial fluxgate magnetometer called MAM. MAM acquired vector samples at 3 s intervals in two resolutions: 32 nT (L-range, at radial distances less than about 5 Re) and 0.125 nT (H-range, at 5-7.1 Re). MAM data are available for the period from October 26, 1994 to July 5, 1996. See Nagai e t al. [1996] for details.

Magnetometer Summary Plots
(Not for use in publications or public presentations)

1994  Oct  Nov  Dec

1995  Jan  Feb  Mar  Apr  May  Jun
      Jul  Aug  Sep  Oct  Nov  Dec

1996  Jan  Feb  Mar  Apr  May  Jun

Each plot spans a 14-hour time interval, approximately equal to the satellite orbital period, and is centered on the satellite apogee. The field components are given in the dipole VDH coordinate system where H is parallel to the Earth's dipole axis and points northward, D points magnetically eastward, and V is perpendicular to both H and D and points outward. B is the field magnitude calculated from the vector components. The elevation angle Elev measured from the V-D plane and the azimuth Azim about the H axis are also shown.

The location of the satellite is shown at the bottom of the image: R is geocentric distance in Earth radii, MLAT is dipole latitude in degrees, MLT is dipole local time in hours, and GLON is geographic longitude in degrees.

The plots should not be used for public publications or presentations. The data are presented without correction except for removing a fixed-value satellite field. The real satellite field is a function of both time and satellite position relative to the Earth. The residual satellite field could be on the order of 10 nT. No efforts have been made to remove anomalous data points or interference from other experiments on the satellite. Those who wish to use MAM data should contact one of the individuals listed below to get information on the quality of the data.

Data Request

Digital MAM data are available upon request. Contact:

Tsugunobu Nagai
Tokyo Institute of Technology


Kazue Takahashi
Solar-Terrestrial Environment Laboratory, Nagoya University
(e-mail: kazue #


Nagai, T., T. Ondoh, H. Matsumoto, T. Goka, T. Fukuda, M. Nose, T. Iyemori, K. Takahashi, and S. Kokubun, ETS-VI magnetic field observations of the near-earth magnetotail during substorms, J. Geomag. Geoelectr., 48, 741-748, 1996.

This site is maintained by:
Kazue Takahashi (kazue #